Increasing amounts of waste generated from used engine oil and used antifreeze are produced each year. For instance, it is estimated that approximately 2,000,000 tons of used antifreeze and 30,000 tons of used brake fluid are generated Annually in the world. Most or all of this waste material must be disposed of or recycled. In the United States and Japan it is estimated that about 650,000 tons and 70,000 tons, respectively, of used antifreeze are generated every year. These estimates of the amounts of used antifreeze in the United States and Japan do not include the amounts of water added to the antifreeze when the antifreeze is used for most purposes. In the United States, antifreeze is generally used at about a 1:1 ratio with water. Therefore, estimates of the amounts of used antifreeze solution generated should be on the order of twice the figures given above.
One of the conventional processes used to treat these waste fluids is incineration, but the process is cumbersome since the waste materials to be treated are fluids. Solidification of these waste fluids prior to a waste fluid treatment, such as incineration, was considered as an alternative to incineration of liquid forms.
The use of conventional water absorbent polymer materials for solidification of water-containing (aqueous) waste fluids has been well documented. Acrylic polymers represent one type of such water-absorbent material. However, aqueous waste fluids that contain oils and fats and other impurities frequently are not converted to a desirable solid state when such a water absorbent polymer is added. This is because the water absorption rate and the water absorption capability of the water-absorbent polymer materials are reduced in the presence of oils, fats and other such impurities.
Therefore, there is a need to develop a treatment technology which can convert aqueous waste fluids that contain oils and fats and other impurities, or even comparable waste fluids that do not contain water, into a desirable solid state. An object of the present invention is development of such a treatment technology for conversion of the described waste fluids to usable solid states.